This invention relates generally to the field of surgical trocar systems which provide a sealed passageway for insertion and removal of various instruments through a hole in the body wall to reach an internal cavity, where a hollow, tubular cannula maintains an open channel and one or more valves define a seal to close the open channel when no instrument is inserted as well as to seal around an inserted instrument. More particularly, the invention relates to such devices where the trocar assembly is formed of detachable component members, such that the valves are disposable yet the cannula may be sterilized and reused.
Trocar systems are well known in the surgical field. In many procedures, such as laporascopic surgery, access to an internal cavity is achieved by puncturing a relatively small hole through the body wall using a pointed trocar in combination with a tubular cannula, or a sharpened cannula/trocar in combination with an internal obturator. The pointed trocar or obturator is removed from the hollow cannula to open the passageway and typically the internal cavity is distended by introducing a gas into the cavity. A valve seal made of an elastomeric material is used to seal the cannula to prevent escape of the gas from the cavity. Slits or other aperture means in the seal allow an instrument to be inserted through the valve to perform an operation in the internal cavity. Since the instrument must be smaller in outer diameter than the inner diameter of the cannula to allow for insertion and relative movement within the cannula, the seal, or an additional seal, is designed to also prevent gas from escaping through the cannula past the instrument. There are numerous examples of such trocar systems in the art, as well as numerous constructions for the valve seals.